Wet electrostatic precipitators have been used for many years to remove dust, acid mist and other particulates from water-saturated air and other gases by electrostatic means. In a WESP, particulates and/or mist laden water-saturated air flows in a region of the precipitator between discharge and collecting electrodes, where the particulates and/or mist is electrically charged by corona emitted from the high voltage discharge electrodes. As the water-saturated gas flows further within the WESP, the charged particulate matter and/or mist is electrostatically attracted to grounded collecting plates or electrodes where it is collected. The accumulated materials are continuously washed off by both an irrigating film of water and periodic flushing.
This type of system is used to remove pollutants from the gas streams exhausting from various industrial sources, such as incinerators, wood products manufacturing, coke ovens, glass furnaces, non-ferrous metallurgical plants, coal-fired generation plants, forest product facilities, food drying plants and petrochemical plants.
Traditionally, the collecting surfaces and other parts of electrostatic precipitators exposed to the process gas stream have been fabricated from carbon steel, stainless steel, corrosion and temperature resistant alloys, lead and fiberglass reinforced plastics. However, such materials tend to corrode and/or degrade over time especially when the precipitators are used in severe environments. Carbon and stainless steel tend to corrode or erode under severe acid conditions. Reinforced plastics tend to erode and/or delaminate due to severe corrosive conditions and localized high temperature in regions of sparking.
There is, therefore, a need to manufacture components exposed to a gas stream within a wet electrostatic precipitator that are not only corrosion resistant under severe industrial environments, but also electrically conductive and resistant to localized high temperatures due to sparking and arcing.